The present invention relates to a communication apparatus configured to transmit and receive frames. More particularly, the present invention relates to a communication apparatus configured to diagnose failures occurring at a CAM (Contents Addressable Memory) configured to conduct high speed table search.
Japanese Patent Publication No. 2005-117171 (Patent Document 1) and Japanese Patent Publication No. 2000-20533 (Patent Document 2) disclose the background technology of the present field. Patent Document 1 discloses the following description: “The packet transfer apparatus is provided with a search key storage section 101 for storing a searching key relative to a packet transfer destination and collation information generated by the searching key in cross-reference with a storage address of the transfer information stored in a transfer information storage section 104, a transmission information acquisition section 103 uses the searching key generated on the basis of header information and the collation information generated from the searching key to search a searching key storage section 101, and when they are coincident with the searching key and the collation information stored in the searching key storage section 101, the transmission information acquisition section 103 acquires the storage position information of the transfer information from the searching key storage section 101, acquires the transfer information stored in the transfer information storage section 104 on the basis of the acquired storage address information and a transfer section 106 transfers packets on the basis of the acquired transfer information.” (See “Abstract”).
Patent Document 2 discloses the following description: “The fault detector is provided with a CAM 1 for outputting a retrieval coincidence flag when data coincident with retrieving data are stored, an address generation part 2 for connecting a retrieval coincidence address to the address input of the CAM 1 in accordance with a retrieval instruction from the external and the retrieval coincidence flag and a data generation part 3 for connecting the retrieving data to the data input of the CAM in accordance with the retrieval coincidence flag and constituted so as to judge a fault in the retrieving circuit by comparing, in a comparison part 4, data stored in the retrieval coincidence address of the CAM 1 with the retrieving data generated from the data generation part 3.” (See “Abstract”).    [Patent Document 1] Japanese Patent Publication No. 2005-117171    [Patent Document 2] Japanese Patent Publication No. 2000-20533